Morphology evolution of core–shell carbon@mesoporous carbon microspheres with excellent microwave absorption performance

Abstract

Carbon microspheres have been widely applied in the microwave absorption (MA) field, but consecutively regulating the microstructure still remains a great challenge. In this paper, we developed a facile templated method to fabricate unique core–shell carbon@mesoporous carbon microspheres with an adjustable core and shell. By tuning the nucleation time of the carbon core, the morphology configuration can evolve from a hollow to a core–shell structure. As the nucleation time increases, the size of core carbon is gradually improved with a simultaneous reduction in the thickness of the mesoporous shell. It is confirmed that the morphology evolution of core–shell microspheres greatly affects the complex permittivity and MA performance. When the nucleation time is set as 8 h, microspheres with a moderate carbon core and mesoporous shell present efficient MA properties with a strong reflection loss intensity of −46.9 dB and wide absorption bandwidth of 7.28 GHz at a thickness of 2.4 mm. The relationship between the microstructure evolution and complex permittivity and the microwave dissipation mechanism are also investigated. This work may shed light on the microstructure regulation to optimize the dielectric ability and MA properties.